Generally, when bars and wires of, for example, metal are produced continuously, a process is widely adopted wherein rolling rolls, the outer circumferential surfaces of which have forming grooves formed therein, are used to continuously roll a metal material. To perform such rolling, so-called cantilevered rolling rolls are used, each of which has a shaft with one end connected to an output shaft of a rolling mill, as disclosed in, for example, Japanese Patent No. 3,116,040. In addition, the rolling rolls, each of which is configured by detachably assembling a rolling ring that is made of a hard material, such as cemented carbide, to the outer circumference of the shaft, are used to finish the surface of the product (e.g., wires or bars) so that it is smooth after the material is rolled downstream of the continuous rolling process.
FIG. 14 shows one example of a conventional rolling roll. A rolling roll 1 is formed from, for example, steel and has a shaft 2 that has a substantially columnar shape that extends along an axis L; furthermore, the rolling roll 1 is cantilevered such that one end side (the left side in FIG. 14) of the shaft 2 is connected to the output shaft of the rolling mill (not shown). A tapered part 3 is formed on another end side (the right side in FIG. 14) of the shaft 2 and has an outer diameter that gradually decreases toward the other end side; in addition, a multistepped, columnar small diameter part 4 is further formed on the other end side of the tapered part 3.
A sleeve member 5, which has a tapered hole 6 that is capable of mating with the tapered part 3, is mounted to the shaft 2 from the other end side thereof. The outer circumferential surface of the sleeve member 5 is a cylindrical surface that is parallel to the axis L and is configured so that the wall thickness of the sleeve member 5 gradually thins toward the one end side. In addition, a through hole 7, which extends so that it is coaxial with the tapered hole 6, is drilled in the other end side of the sleeve member 5, and the small diameter part 4 of the shaft 2 is inserted therein.
A substantially toric rolling ring 8, which is formed from a hard material such as cemented carbide, is disposed on the outer circumferential side of the sleeve member 5. A forming groove 9, which has a semicircular cross section and is recessed radially toward the inner side, is formed in the outer circumferential surface of the rolling ring 8 at its center part in the directions of the axis L, and an inner circumferential surface of the rolling ring 8 is a cylindrical surface that is parallel to the axis L.
Here, by moving the sleeve member 5, which is mounted to the shaft 2, to the one end side, the tapered part 3 deforms the sleeve member 5 such that it widens radially toward the outer side. In so doing, the sleeve member 5 presses the inner circumferential surface of the rolling ring 8 so that it widens radially toward the outer side, thereby fixing the rolling ring 8 to the outer circumferential surface of the sleeve member 5. Here, the shaft 2 and the sleeve member 5 are fixed by taper mating, and therefore the rolling roll 1 is configured such that the shaft 2, the sleeve member 5, and the rolling ring 8 are integral.